Editing Two-stroke engine (section)

====Cross-flow scavenging====
[[File:Two-stroke deflector piston (Autocar Handbook, 13th ed, 1935).jpg|thumb|upright|[[Deflector piston]] with cross-flow scavenging]]
In a cross-flow engine, the transfer and exhaust ports are on opposite sides of the cylinder, and a [[deflector piston|deflector]] on the top of the piston directs the fresh intake charge into the upper part of the cylinder, pushing the residual [[exhaust gas]] down the other side of the deflector and out the exhaust port.<ref name="Irving, 13" >
{{cite book
 |title=Two-Stroke Power Units
 |last=Irving |first=P.E.
 |author-link=Phil Irving
 |year=1967
 |publisher=Newnes
 |pages=13–15
 |ref={{harvid|Irving|Two stroke power units}}
}}</ref> The deflector increases the piston's weight and exposed surface area, and the fact that it makes piston cooling and achieving an effective combustion chamber shape more difficult is why this design has been largely superseded by uniflow scavenging after the 1960s, especially for motorcycles, but for smaller or slower engines using direct injection, the deflector piston can still be an acceptable approach.